Continued phone 'porting' problems

After trying to assign me a new phone number, Comcast has finally got around to 'porting' the number over. I'm assuming the number has been, at least, partially ported over since the number they tried to give me no longer works and I am now able to setup a Comcast voicemail with my old number. However, no calls are coming through to the number. I need that fixed and I need to know if it is safe to cancel with my old phone service.